/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.plan.execution.config.metadata;

import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.SettableFuture;
import org.apache.iotdb.commons.udf.UDFInformation;
import org.apache.iotdb.commons.udf.builtin.BuiltinAggregationFunction;
import org.apache.iotdb.commons.udf.service.UDFManagementService;
import org.apache.iotdb.db.mpp.common.header.ColumnHeader;
import org.apache.iotdb.db.mpp.common.header.ColumnHeaderConstant;
import org.apache.iotdb.db.mpp.common.header.DatasetHeader;
import org.apache.iotdb.db.mpp.common.header.DatasetHeaderFactory;
import org.apache.iotdb.db.mpp.plan.execution.config.ConfigTaskResult;
import org.apache.iotdb.db.mpp.plan.execution.config.IConfigTask;
import org.apache.iotdb.db.mpp.plan.execution.config.executor.IConfigTaskExecutor;
import org.apache.iotdb.rpc.TSStatusCode;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.tsfile.read.common.block.TsBlockBuilder;
import org.apache.iotdb.tsfile.utils.Binary;

import java.lang.reflect.InvocationTargetException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

import static org.apache.iotdb.commons.conf.IoTDBConstant.*;

public class ShowFunctionsTask implements IConfigTask {

    @Override
    public ListenableFuture<ConfigTaskResult> execute(IConfigTaskExecutor configTaskExecutor) {
        return configTaskExecutor.showFunctions();
    }

    public static void buildTsBlock(
            List<ByteBuffer> allUDFInformation, SettableFuture<ConfigTaskResult> future) {
        List<TSDataType> outputDataTypes =
                ColumnHeaderConstant.showFunctionsColumnHeaders.stream()
                        .map(ColumnHeader::getColumnType)
                        .collect(Collectors.toList());
        TsBlockBuilder builder = new TsBlockBuilder(outputDataTypes);
        List<UDFInformation> udfInformations = new ArrayList<>();
        if (allUDFInformation != null && !allUDFInformation.isEmpty()) {
            for (ByteBuffer udfInformationByteBuffer : allUDFInformation) {
                UDFInformation udfInformation = UDFInformation.deserialize(udfInformationByteBuffer);
                udfInformations.add(udfInformation);
            }
        }
        // native and built-in functions
        udfInformations.addAll(
                UDFManagementService.getInstance().getAllBuiltInTimeSeriesGeneratingInformation());

        udfInformations.sort(Comparator.comparing(UDFInformation::getFunctionName));
        for (UDFInformation udfInformation : udfInformations) {
            appendUDFInformation(builder, udfInformation);
        }
        appendNativeFunctions(builder);
        DatasetHeader datasetHeader = DatasetHeaderFactory.getShowFunctionsHeader();
        future.set(new ConfigTaskResult(TSStatusCode.SUCCESS_STATUS, builder.build(), datasetHeader));
    }

    private static void appendUDFInformation(TsBlockBuilder builder, UDFInformation udfInformation) {
        builder.getTimeColumnBuilder().writeLong(0L);
        builder.getColumnBuilder(0).writeBinary(Binary.valueOf(udfInformation.getFunctionName()));
        builder.getColumnBuilder(1).writeBinary(Binary.valueOf(getFunctionType(udfInformation)));
        builder.getColumnBuilder(2).writeBinary(Binary.valueOf(udfInformation.getClassName()));
        builder.declarePosition();
    }

    private static void appendNativeFunctions(TsBlockBuilder builder) {
        final Binary functionType = Binary.valueOf(FUNCTION_TYPE_NATIVE);
        final Binary className = Binary.valueOf("");
        for (String functionName : BuiltinAggregationFunction.getNativeFunctionNames()) {
            builder.getTimeColumnBuilder().writeLong(0L);
            builder.getColumnBuilder(0).writeBinary(Binary.valueOf(functionName.toUpperCase()));
            builder.getColumnBuilder(1).writeBinary(functionType);
            builder.getColumnBuilder(2).writeBinary(className);
            builder.declarePosition();
        }
    }

    private static String getFunctionType(UDFInformation udfInformation) {
        String functionType = FUNCTION_TYPE_EXTERNAL_UDTF;
        try {
            if (udfInformation.isBuiltin()) {
                if (UDFManagementService.getInstance().isUDTF(udfInformation.getFunctionName())) {
                    functionType = FUNCTION_TYPE_BUILTIN_UDTF;
                } else if (UDFManagementService.getInstance().isUDAF(udfInformation.getFunctionName())) {
                    functionType = FUNCTION_TYPE_BUILTIN_UDAF;
                }
            } else {
                if (UDFManagementService.getInstance().isUDTF(udfInformation.getFunctionName())) {
                    functionType = FUNCTION_TYPE_EXTERNAL_UDTF;
                } else if (UDFManagementService.getInstance().isUDAF(udfInformation.getFunctionName())) {
                    functionType = FUNCTION_TYPE_EXTERNAL_UDAF;
                }
            }
        } catch (InstantiationException
                | InvocationTargetException
                | NoSuchMethodException
                | IllegalAccessException ignore) {
        }
        return functionType;
    }
}
